Variations in Corn Yield and Nitrogen Uptake in Relation to Soil Attributes and Nitrogen Availability Indices

Abstract

Identification of soil attributes most determinant to crop yield is still a matter of debate. The main objective of the present study was to relate the variations in corn (Zea mays L.) yield and N uptake to 16 soil attributes. Samples were collected in 2005 and 2006 from a long‐term experiment. Soil organic C (SOC), total N (TN), potential mineralizable N (PMN), NO3 extractable with KCl (NO3–KCl) and CaCl2 (NO3–CaCl2), NO3 adsorbed on anion exchange membranes (NO3–AEM), N extracted with NaHCO3 read at 205 nm (N‐NaHCO3−205) and 220 nm (N‐NaHCO3−220), N present in fulvic acid (FA‐N), humic acid (HA‐N) and non‐humified fractions (NHF‐N), mean weight diameter of aggregates (MWD), total, macro‐ and microporosity, and bulk density (Db) were measured. Principal component analysis (PCA) was conducted with the measured soil attributes, and the principal components (PCs) were used in a stepwise regression with corn yield and N uptake. In both years, a maximum of 88% of the total variance was explained. The stepwise regression analysis indicated that the first two PCs explained 78 to 91% of the variability in corn yield and N uptake. Based on the PCA, TN, HA‐N, NO3–KCl, NO3–CaCl2, NO3–AEM, and PMN appeared as primary indicators of corn yield and N uptake, whereas MWD, FA‐N, and NHF‐N appeared as secondary indicators. When the variability in corn yield and N uptake explained by each N availability index was assessed, NO3–KCl and NO3–CaCl2 appeared as the best predictors of corn yield because of their ease of measurement and reliability across years.